j1708 + easylink analyser
Stereo Audio Mixer
| Manual |
Version 1.02
Table of contents
3.2.1 16 / 24 bits mode selection
3.2.2 Checking recording buffer state
2 2 3 3 3 4 5 5 6 6 7 7 7 8 1. General description
MM-4220 includes:
• 4 low-noise mic/line inputs
• Compact Flash recorder
• Re-chargeable batteries
• Heavy-duty metal case
• Compact size
• 1 kHz test tone
• 48V phantom power
• AES3-id digital out
The MM-4220 is a true professional stereo Mixer for portable use, made by MARENIUS.
It offers four mic/line input channels, built-in Compact Flash card recorder, PPM
metering with 2 x 8 multicolored LED’s, low-noise amplifiers and power supply based on
re-chargeable NiMH cells for up to 8 hours use. All this is housed in a compact, all-metal
heavy-duty case.
The front panel holds all controls for the mixer. On top of the panel are toggle switches for
Power, Test Tone and Battery Test.
48V phantom power may be selected for 0, 2 or 4 inputs.
Each of the four channels has a gain control pot and a pan pot. In addition there is a gain
selector switch for 0, 24 or 48 dB gain. The gain pot adds up to 12 dB and the master pot adds
another 12 dB for a total of 72 dB gain, input-to-output.
There is also a toggle switch for inserting a HP-filter for wind and bass cut.
On the upper part of the front panel is the PPM bar graph with 16 multicolor LED’s covering the
range -50 to 0 dB in optimized step size.
You will also find the master pot and the headphones pot, as well as a switch for selecting 48V
phantom power for 0, 2 or 4 channels.
The CF card slot will accept up to 16 GB cards. Recordings are saved in uncompressed WAV
format on FAT32 formatted cards.
Recordings are stereo, 16-24 bits @ 48 kHz, selectable in setup menu by a PC connected to
the USB port, or by front panel switches during power-up.
The backside panel holds all sockets for inputs, outputs and external power supply.
There are four input sockets (XLR-3F) for the input channels and two sockets (XLR-3M) for the
main outputs L and R.
A 3.5 mm stereo socket is intended for headphones (32 - 2000 ohms impedance).
There is also an AES3-id RCA socket output and a USB socket for configuration of the mixer.
External power supply can be used for prolonged working time or when the mixer is used in a
non-portable mode.
The external power should be 18 V @ 1 A.
When powered from internal accumulator, expect a total working time of 6-8 hours, depending
on battery status and temperature.
A high-speed charger function is included for a charging time of about 2.5 hours.
2. Connections
2.1 Power supply
The 2,1 mm power jack on the back of the unit accepts a clean DC voltage for powering and/or
charging. The polarity can be switched without damaging the mixer.
Input voltage: 18 VDC
Minimum input current: 1000 mA
! Caution: Voltages above the recommended supply voltage can damage the device.
2.2 Audio inputs
The mixer has four balanced XLR3 female sockets for mic or line level signals.
The pin configuration of the analog inputs is shown in table 2.1.
Table 2.1
Balanced analog audio input
Connector type
XLR Female
Pin 1
Pin 2
Pin 3
In case a line level signal is connected, make sure the 48V front panel switch is set to OFF (mid
For an unbalanced line level signal connect in accordance with table 2.2.
Table 2.2
Unbalanced analog audio input
Connector type
XLR Female
Pin 1
Pin 2
Pin 3
2.3 Audio outputs
There are two balanced XLR3 male sockets for line level outputs.
The pin configuration of the analog outputs is shown in table 2.3.
Table 2.3
Balanced analog audio output
Connector type
XLR Male
Pin 1
Pin 2
Pin 3
For an unbalanced line level output signal connect in accordance with table 2.4.
Table 2.4
Unbalanced analog audio output
Connector type
Do not connect!
XLR Male
Pin 1
Pin 2
Pin 3
2.4 Phones output
The headphones output is a 3.5 mm 3-pole socket for standard headphones with an impedance
equal to 32 - 2000 ohms.
Table 2.5
Phones output
Connector type
3.5 mm, 3-pole
2.5 Digital output
The digital audio output conforms to the AES3-id format.
This is essentially a professional AES/EBU format in an unbalanced RCA socket.
Data format is AES/EBU3 while electrical interface is equal to that for coaxial S/PDIF (0,5 Vpp,
75 ohms).
Table 2.6
Unbalanced digital audio output
Connector type
2.6 USB socket
The mixer has a mini-USB socket for connection to a PC for setting the internal real-time clock.
This is used for adding a time-stamp to each recording.
Instructions for setting the clock are described in chapter 3.3 in this manual.
The USB socket is also used for setting 16 or 24 bits recording resolution.
The USB socket may also be used for software updates.
Instructions for use are included with the update, when available.
Check for updates frequently at http://www.marenius.se.
3. User instructions
3.1 Audio Mixer
The audio mixer functions are very straight-forward.
• Connect desired number of microphones and/or line level input signals to the XLR
sockets INPUT1 - 4 on the back panel.
• If required, connect the output signal from the XLR sockets OUTPUT LEFT and RIGHT.
• If required, connect a headphone to the phones socket.
• If required connect the digital output to an external unit with a suitable digital input.
• If available, use mains power supply through the mains adapter/charger unit.
• Set the 48V switch to off, mid position.
• Power-on the mixer by the toggle switch POWER.
• Check battery status by setting TEST switch to BAT position. The lower meter will
indicate the battery status between 0% and 100%.
• Turn gain control knobs 1 – 4 fully down, anti-clockwise.
• Set MASTER knob to 0 dB.
• Switch on the 1 kHz TEST tone, left position. The test tone is a highly stable and very
low-distortion sine wave.
• The output signal on the XLR sockets is 12 dB higher than what is indicated by the PPM
meter. This is because MM-4220 is basically a digital mixer/recorder with a maximum
signal level = 0 dB. At this maximum level the maximum output level on the XLR line
outputs is +12 dBu.
• Calibrate the gain in external analog equipment that is connected to the XLR line output
sockets. (Equipment connected to the digital output needs no gain calibration.)
MM-4220 is now ready to be used as an ordinary mixer.
• Select 48V phantom power for microphone inputs 1 and 2 or 1, 2, 3 and 4 if required.
Note that the sum of all phantom currents used must not exceed 5 mA. Also note that
phantom power does drain the battery more.
• Adjust gain for each input by turning the knob and setting the 3-way gain switch in
0/24/48 dB position, as required.
• Adjust panning by turning the PAN pot.
• Select low-cut HPF filter if required. This may be useful for cutting wind noise.
• Adjust the phones knob for a good listening level with headphones.
The MASTER knob may be used for adjusting the sum of all inputs. However, it is advised that
it is left in the range close to 0 dBu.
Setting master knob to a low value while any of the inputs has too much gain will result in
distortion. On the other hand, setting the master knob to a high value while the inputs are set to
low gain may increase the noise level.
Good audio mixing is a question of balance between noise floor and
clipping level, for maximum dynamic range.
3.2 Audio Recorder
The Compact Flash Recorder is located close to the left edge of the front panel.
Before use a formatted CF card is required. Use a suitable CF card adapter connected to a PC
(or Mac) and format the card according to the FAT32 standard. Any other formats will be
useless in MM-4220.
Suitable CF cards have a capacity between 2 GB and up. High-speed cards are preferred.
For 24 bits recordings this is required. Some example CF cards that usually work with this mixer
are KINGSTON 133x and 266x and SANDISK Ultra III.
Do not put any other files onto the card, only files generated by MM-4220 should be on it.
The card fits into the front panel slot, facing left.
When a CF card is inserted and found to be correct the MODE LED will be violet, Otherwise it
will be blue.
There are five keys for controlling the recorder:
>> >>
is used for skipping forward between recordings and within recordings.
This key is valid only while in playback mode.
A brief press will skip to next file (unless file played is the last recorded).
Press-hold will skip forward within the file.
<< <<
is used for skipping backwards between recordings and within recordings.
This key is valid only while in playback mode.
A brief press will skip to previous file (unless file played is the first recorded).
Press-hold will skip backwards within the file.
This is the STOP key. It will end a recording and save the file with a new file
number. In playback mode it will halt playback and return the mixer outputs to
mixer mode.
This is the RECORD key. Pressing it will immediately start a new recording.
The MODE LED will turn red.
This is the PLAYBACK key. The last file recorded will play back when this key is
pressed. The MODE LED will turn green.
Pressing it again will enter PAUSE mode and the MODE LED will flash.
Files are recorded in uncompressed standard Wav-format with 48 kHz sample rate and 16 or
24 bits resolution. The files are automatically numbered REC00000.wav and up. Each file will
get a correct time stamp, provided the real-time clock has been set correctly.
Maximum length for a single file is 2 hours.
Files recorded may be played back in any PC or Mac directly from the CF card, with a suitable
CF card reader.
3.2.1 16 / 24 bits mode selection
For selecting 24 bits recording mode, hold the >> >> key while powering on the mixer.
The bar graph will show 3 + 3 LEDs lit.
For selecting 16 bits recording mode, hold the << << key while powering on the mixer.
The bar graph will show 2 + 2 LEDs lit.
3.2.2 Checking recording buffer state
The recording buffer is an on-board memory that holds enough samples for compensating for
the periodically slower CF card.
With some CF cards and, in particular, in 24 bits mode there may be risqué for buffer overrun.
To see the buffer status, press both keys >> >> and << << while in recording mode.
The bar graph will show a low level for a good state and a higher level for buffer problem.
In case of buffer overrun recording mode is cancelled.
3.3 Setting the internal clock
There are a few steps to perform in order to set the clock.
1. Download the most suitable Windows or Mac driver for the USB COM port from
http://www.ftdichip.com/Drivers/VCP.htm and unzip the files to a separate folder.
2. Power on MM-4220. IMPORTANT! Do this before connecting the USB cable.
Also, remove the CF card, if one is inserted!
3. Connect a USB cable between the PC and MM-4220. Avoid using a USB hub, a
direct USB socket is preferred.
4. The ‘found new hardware’ wizard starts. Follow the on-screen instructions, pointing
the wizard to the folder where the unzipped driver files are located. If a window
appears with a note about the driver not being verified, agree to install anyway.
5. When done a message will show up indicating that the driver for a USB serial
converter has been installed.
6. To see what COM port number has been assigned to the USB COM port, look into
the Control Panel / Hardware Devices / Ports.
7. Use a terminal software of your choice. An example is Tera Term, available for free
from http://www.ayera.com/teraterm/.
8. Run the terminal software and make sure to select the COM port that was previously
indicated to be used for the MM-4220 connection.
Communication parameters are 9600,N,8,1.
9. Hit <Enter>. A short menu will show up. It has three choices:
T Set time
D Set date
R Recording resolution
Q Quit
10. When done, power off MM-4220 and disconnect the USB cable.
3.4 Power Supply
MM-4220 runs from an internal NiMH power pack. This is a high capacity pack with rechargeable accumulators for a full working day without need for additional charging.
The included mains adapter/charger unit can be used for both charging and powering the mixer.
The power supply has a 2.1 mm plug, polarity is any. For both powering and charging the
minimum current capacity must be 1 A @ 18 V DC.
When connected the LED next to the socket will be lit red. When the mixer is fully charged the
LED will be lit green. This may take up to 2,5 hours for a fully discharged unit.
There is no need to discharge the unit before charging.
The internal, intelligent charging circuitry handles the complete charging cycle.
4. Technical specifications
Frequency range
Max. gain
Signal-to-noise ratio
Crosstalk at full pan
Equiv. input ref. noise
Input sockets
Audio input impedance
Audio input level max.
High-pass filter
Output sockets
Audio output impedance
Audio output level max.
Phones socket
Phones output
Phones impedance
Digital output
Sampling frequency
A/D resolution
A/D dynamic range
D/A resolution
D/A dynamic range
File memory
File type
Recorder functions
Test tone
Phantom power
Power supply
Current drain
Charge current
Size W x H x D
Battery charger
Carrying case
25 Hz -22 kHz (-3 dB)
<0,004% @ 1 kHz, +12 dBu output level
72 dB (48+12+12)
>94 dB@0 dB gain, A-weight
<-50 dB
<-122 dBu, A-weighted @max gain
2 K ohms (mic), 20 K ohms (line)
+12 dBu
-3 dB @ 180 Hz, -20 dB @ 30 Hz
2 x 100 ohms balanced
+12 dBm (600 ohms)
3.5 mm 3-pole
2.0 Vrms into 300 ohms
32 - 2000 ohms
AES3-id, 75 ohms, 1 Vpp, S/PDIF compatible, RCA
48 kHz
24 bits
98 dB, A-weighted
24 bits
98 dB, A-weighted
Compact Flash, type I, FAT32 formatted, max 16 GB
WAV, stereo, uncompressed, 48/16-24
2x8 LED´s, 3 colors, PPM mode
1000 Hz +/-0,001% @ -12 dBFS (0 dBu) output level
48 V+-6 V, max 5 mA @ 90%
internal NiMH or ext. 18 V DC@1 A
<220 mA
750 mA
approx. 140 x 60 x 136 mm, excl. sockets and knobs
approx. 950 grams
included, 90-240 VAC
PortaBrace original, optional
Specifications are subject to change without notice.
Box contains:
MM-4220 Stereo Mixer / Recorder
Mains adapter / charger 18V
CF card
USB cable
User´s manual
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